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Projections of the hand field of the macaque ventral premotor area F5 to the brainstem and spinal cord
Author(s) -
Borra Elena,
Belmalih Abdelouahed,
Gerbella Marzio,
Rozzi Stefano,
Luppino Giuseppe
Publication year - 2010
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/cne.22353
Subject(s) - neuroscience , spinal cord , brainstem , premotor cortex , reticular formation , biology , macaque , superior colliculus , anatomy , motor control , motor cortex , motor neuron , primary motor cortex , motor system , dorsum , central nervous system , stimulation
In the present study we first assessed that the hand motor field of the macaque ventral premotor area F5, involved in visuomotor control of hand actions, is connected to both the hand field of the primary motor cortex (M1) and the spinal cord. We then injected retroanterograde tracers in this field to completely illustrate its possible descending motor projections. In the brainstem the F5 hand motor field projects to the intermediate and deep layers of the superior colliculus (SC) and to sectors of the mesencephalic, pontine, and bulbar reticular formation, which are the sources of spinal projections. In the spinal cord, labeled terminals were virtually all confined to the C2–T1 segments, mostly contralaterally. At C6–T1 levels the labeling was weaker and mostly clustered laterally in the intermediate zone. At C2–C5 levels, labeled terminals were much denser and diffusely distributed over the mid‐dorsal part of the intermediate zone where a propriospinal system that directly controls hand muscle motoneurons and mediates commands for the control of dexterous finger movements is located (Isa et al. [2007] Physiology 22:145–152). Thus, the F5 hand motor field has a weaker direct access and a stronger indirect access to spinal segments where hand muscle motoneurons are located, suggesting a role of this field in the generation and control of hand movements not only at the M1 level, but also at the spinal cord level. These projections may represent the neural substrate for the F5 hand motor field's role in the recovery of manual dexterity after M1 lesions. J. Comp. Neurol. 518:2570–2591, 2010. © 2010 Wiley‐Liss, Inc.